Interior permanent magnet rotor

Abstract

A rotor includes a rotor core having i) a plurality of magnet insertion holes formed at predetermined intervals in a circumferential direction and into which magnets are inserted and ii) a void section communicating with one end of each of the plurality of magnet insertion holes, a yoke provided inside each of a plurality of the void sections so as to be movable in a radial direction of the rotor core, and an elastic member provided inside each of the plurality of the void sections and pressing the yoke in the radial direction.

1 . An interior permanent magnet rotor comprising:
 a rotor core having i) a plurality of magnet insertion holes formed at predetermined intervals in a circumferential direction and into which magnets are inserted and ii) a void section communicating with one end of each of the plurality of magnet insertion holes;   a yoke provided inside each of a plurality of the void sections so as to be movable in a radial direction of the rotor core; and   an elastic member provided inside each of the plurality of the void sections and pressing the yoke in the radial direction.   
     
     
         2 . The interior permanent magnet rotor according to  claim 1 , wherein
 the yoke includes i) a first yoke portion located on a side closer to the magnet insertion hole in the circumferential direction, and ii) a second yoke portion that is located on a side farther from the magnet insertion hole in the circumferential direction and is longer than the first yoke portion in the radial direction, and   the elastic member is provided between an end surface of the void section and the first yoke portion along the radial direction.   
     
     
         3 . The interior permanent magnet rotor according to  claim 2 , wherein
 the void section includes i) a first void portion located closer to the magnet insertion hole in the circumferential direction and in which the first yoke portion can move in the radial direction and the elastic member can expand and contract, and ii) a second void portion located farther from the magnet insertion hole in the circumferential direction and in which the second yoke portion can move in the radial direction, and   the first yoke portion and the second yoke portion pressed by the elastic member are in contact with an end surface of the void section positioned inward in the radial direction.   
     
     
         4 . The interior permanent magnet rotor according to  claim 3 , wherein
 the second yoke portion approaches an end surface of the second void portion positioned outward in the radial direction when the elastic member compresses.   
     
     
         5 . The interior permanent magnet rotor according to  claim 3 , wherein
 the second yoke portion is located at a position so as not to come into contact with an end surface of the second void portion in the radial direction when the elastic member compresses the most.   
     
     
         6 . The interior permanent magnet rotor according to  claim 3 , wherein
 a cross-sectional area of the second yoke portion, taken along a plane orthogonal to the radial direction, is smaller toward an end surface of the second yoke portion positioned outward in the radial direction.   
     
     
         7 . The interior permanent magnet rotor according to  claim 1 , wherein
 when a rotational speed of the rotor core exceeds a base rotational speed, the elastic member compresses by being pressed by a centrifugal force acting on the yoke as the rotational speed increases.   
     
     
         8 . The interior permanent magnet rotor according to  claim 1 , further comprising:
 a support part that is provided between the magnet and the elastic member in each of the plurality of void sections to prevent the elastic member from moving toward the magnet.   
     
     
         9 . The interior permanent magnet rotor according to  claim 1 , wherein
 an end surface of the void section positioned inward in the radial direction is larger than an end surface of the void section positioned outward in the radial direction.